The packaging of a pinfeather is very thin and almost transparent , it's the same material as the feather. Mo/mo on black gives mostly white feathers on chicks so that's on the light side, don't know about other feathercolours and mottled.

Thanks Berend! the reason I am asking, is that dark birds have dark pin feathers which make them difficult to process cleanly- but if a mottle was introduced into the line, the plucked chicken might look cleaner. Just a hypothetical breeding question for now. Sounds promising though.